Crystal indexing fixture



March 1947- w. P. MARSHALL I CRYSTAL INDEXING FIXTURE Filed June 22,1945 3 Sheets-Sheet l -WILBERT RMARSHALL M f 4, 1947' w P. MARSHALL2,416,703

: CRYSTAL INDEXING FIXTURE I Filed June 22, 1945 3 S ee she t 2 I v-71.1111 ll 7 '4 l3 7 WILBERT P. MARSH ALL WWW March 4, 1947 w. MARSHALL2,416,703

\CBYSTAL INDEXING FIXTURE Filed June 22, 1945 I I 3 Sheets-Sheet 3W|LBERT P. MARSHALL I Patented Mar. 4, 1947 UNITED STATES PATENT OFFICEI I I 2,416,703 Y I I CRYSTAL INDEXING FIXTURE Wilbert P. Marshall,Cleveland Heights, Ohio Application June 22, 1945, SerialNo. 501,051

4 Claims. (01. 51:21?)

(Granted under the act of March 3, 1883, as

amended April 30, 1928.; 370 0. G. 757) The present invention has to dowith the production of piezoelectric crystal elements and moreparticularly the cutting of piezoelectric elements from a crystal orportion of a crystalof piezoelectric material with reference to certainaxes of the crystal.

An important requirement to the attainment of accuracy, economy andrapid production in such cutting is the provision of means for firmlyholding the piece of crystal material in various predetermined positionsrelative to the cutting tool, in a manner to afford operation of thetool on a large portion of the material in a single operation, and toafford rapid and accurate re-adjustment of the relative position of tooland workpiece for other operations of the tool on the work-piece withoutdisturbing other angular relations intended to remain constant.

It is therefore an object of the'invention to provide a holding fixturein which the crystal may be adjustably held in any position within asubstantial range of adjustment sufficient to bring crystals ofdiiferent sizes and slight variation in shape, into a position to aligna given axis of the crystal with the cutting plane of the tool,

the fixture being capable of permitting readjustment of theposition ofthe crystal with reference to the tool to change the angular relation ofanother axis or'axes to the tool while maintaining the first alignment.

Another object is to provide in such a fixture, an indexing meanswhereby once the fixture is adjusted to hold the crystal with one axisin alignment with the tool, the crystal may be adjusted about this axisin predetermined angular steps.-

Another object is the provision of means whereby the crystal may beadjusted about the first mentioned axis independently of the indexingmeans.

A further object is to provide a crystal holder which together with thequality of adjustability shall be capable of affording free access to alarge portion of the crystal by the tool.

Various other objects and advantages of the invention will becomeapparent upon perusal of* Fig. l is a perspective view, approximatelyone at Fig. 2, and partly in section.

Fig. 4 is a cross-sectional view of one of the 1 clamping shoes takenthrough the axis of one of the clamping screws in a plane normal to thecross-sectioned portion of Fig. 3.

Fig. 5 is a side elevation on a much reduced scale and in diagrammaticform, showing the crystal holder and a cutting tool in operativerelation.

Referring to the drawings more in detail, the device is comprisedof acarriage element I0 adapted to be removably mounted-on the bedplate llof a cutting tool such as a cutting disk I2, in fixed angular relationto the tool in all three} dimensions, the angular relation being fixedin any known or other suitable manner as by a feather-key or spline [3in slidable engagement with a longitudinal T-slot 14 formed in the bed,while fixation is obtained through clamping bolts I 5 and I6. A supportmember I! pivotally mounted on the carriage l0 through means of 'apintle [8, supports a ring-form crystal holder I9 rotatably mounted inthe support, about an axi parallel to the axis of the pintle l8, bothfixed relative to the carriage I8 and consequently fixed relative to thetool bed I I. i

A pair of leveling screws 20 threaded in the end of the support oppositethe pivoted end and bearing upon the upper surface of the carriage ll],

together with a locking bolt 2|, afford a small angular adjustment ofthe support about the axis of the pintle and consequently an angularadjustment of the holder IS in its plane of rotation for adjustment ofthe holder, and a crystal held therein, to a given starting or zero,angular position with reference to the carriage l0 and tool l2. Clampingshoes 22 carried by the holder'l9, and adjustable radially of the holderthrough clamping bolts 23 in threaded engagement with the holder, serveto adjustably hold and clamp'a crystal to be operated upon, such as thecrystal 24 (Fig. 1'), at various angles to the aXis of the ring-formholder within a substantial range of adjustment sufiicient to ,bring'thelongitudinal axis of crystals of different sizes and slight variation inshape, into alignment with the axis of the ring-form holder,

= To compensate for irregularities in the lateral surfaces of a crystal,the clampingv shoes 22 are v aiforded a slight universal movement eachthrough provision of a slightly loose fit to the ends of its clampingscrews 23, and the provision of a l cork pad 25, the latter, due to itsresiliency, tending to conform to vary slight surface irregularlties.

Loose connection of the shoe '22 with the clamping screw 23 is obtainedthrough the use of a pair of yoke elements 26 secured by screws 21 andembracing the neck portion of the headed end of the clamping screw. 7

The ring-form holder I9 has bearing in the support I! by virtue of itsloose lit in thetwo inwardly facing, annular, rabbeted portions 28formed about the openings 29 in the front and rearplates '30 and 3|which plates with the spacer member 32 constitute the body of the sup-'port H. The plates and spacer member may;

be secured together in any known or other suitable manner as by clampingscrews asshown at 33 in Figs. 1 and 2.

A centering pin 34 passmgthrough registering openings 35 and 36 in thesupport l1 and One of a series of openings 31 in the ring-form holder l9provides means for locking the holder against rotationin the support.)This enables V consequently the crystal to be indexed angularly ineither direction from the starting or zero position by withdrawing thecentering pin, ro-

tating'the holder to bring the next or other desired one of the openings31 into register with the openings in the support, and locking the partsinadjusted position by reinsertion of the alignment tolock the holder inthe new predetermined angular position. I

In operation the crystal 24 is first accurately adjusted and clamped inthe'holder by means of the adjustable clamping shoes and the angularadjustment afiorded by the leveling-screws 20,

to-bring certain axes of the crystalinto a predetermined orientationrelative to the carriage member I0. In the present instance the crystal:24 is one in the form of an elongated rectangul'ar prism withrectangular pyramidal ends, to be cut or sliced along planes parallel tothe longitudinal axis of the crystal and at 45 degrees to the sidefaces. After the crystal has been clamped .in the holder with its threeaxes orientated in parallelism with the threelrectangularaxes(longitudinal, vertica1 and transverse horizontal); of the carriage 10,as indi- 4 tion-determining means on the carriage member I0, enables thecrystal to be originally adjusted in the holder in the desiredorientation with respect to the carriage while situated at some placemore convenient than the tool bed, as on a special adjusting bed orbench not shown, providing ready access to the crystal for theapplication of suitablemeasuring'and indicating devices for deter-'mining'correct adjustment, the spline assuring an orientation of thecarriage with respect to the tool bed the same as it had with the bed orbench on which the alignment of the crystal was established.

I Obviously the original alignment of the crystal may be made with thecarriage mounted on the tool bed. Determination of proper alignment maybe "made in any known or other suitable manner as by determination ofthe angular relation of the crystal faces to the carriage.

While only one practical embodiment of the invention has been hereinshown and described cated in Fig, l,'the carriage being clampedon:

the bed of the cutting tool,--the pin 34,15 withdrawn and the crystalindexed 45 degrees about 'the axis of the holder as indicated in. Fig. 5and locked in this position by're'insertionfof the pin. Now, movement ofthe cutting tool I2 toward the crystal will result in. a slicing cutinto with the longitudinal axis of the original prism but having itssides canted at 45 degreesv to those of the mother crystal.

Provision .ofthe spline l3 or equivalent posifor the sake of disclosure,it is to be understood that the invention is not limited to the specificembodiment disclosed, but contemplates all such modifications andvariations thereof as fall fairly within the scope of the appendedclaims.

. The invention described herein may be manufactured and used by or 'forthe Government of the United States of America for governmentalpurposes-without the payment of any royalties thereon or therefor. r

What is claimed is:

1. A crystal indexing fixture comprising a carriage, a support pivotallymounted on the carriage to swing about an axis fixed relative to thecar.- .riage said support comprising a pair of upright frontand rearplates spaced apart parallel and having circular, openings with rabbetedrims facing each other, a ring form crystal holder mounted between saidplates with its opposite ends fitted into said rabbeted rims forrotation therein, a plurality of pairs ofclamping screws extendingradially through the holder between the plates, each pair terminatingwithin the holder at a work-clampingv shoe supported at spacedpoints onthe ends of the screws for slight universal movement relative thereto,whereby a crystal may be clamped in the ring-form holder and adjusted.angularly with respect to the axis of the ringform holder. I i f 2.- YAcrystal indexing, fixture comprising a car- ...ri'age, a supportpivotally mounted on the care riage to swing about an axis-fixedrelative to the carriage, said support comprising a pair of upright.front and rear plates spaced apart paralleland having circular openingswith rabbeted rims facing each other, a ring form crystal holder mountedbetween said plates with its opposite ends fitted into said rahbetedrims for rotation therein, a plurality .of pairs of clamping screws-means ior locking the ring-form holder in variouspredetermined angularadjustments relative to the support. Y

3. A crystal indexing fixture comprising acarriage; a support pi-votallymounted on the carriage to swing about an axis fixed relative to thecarriage, saidsupport comprising a. pair of upright front and rearplates spaced apart par-3 allel and having circular, openings withrabbeted rims facing each other, a ring form crystal holder mountedbetween said plates with its opposite ends fitted into said rabbetedrims for rotation therein, a plurality of pairs of clamping screwsextending radially through the holder between the plates, each pairterminating within the holder at a work-clamping shoe supported atspaced points on the ends of the screws for slight universal movementrelative thereto, whereby a crystal may be clamped in the ring-formholder and adjusted angularly with respect to the axis of the ring-formholder, together with a centering pin passing through registeringopenings in the plates and one of a circular series of openings in thering form holder.

4. A crystal indexing fixture comprising a carriage, a support pivotallymounted on the carriage to swing about an axis fixed relative to thecarriage, said support comprising a pair of upright front and rearplates spaced apart parallel and having circular openings with rabbetedrims facing each other, a ring form crystal holder mounted between saidplates with its opposite ends fitted into said rabbetedrims for rotationtherein, a plurality of pairs of clamping screws extend- .form holder,the clamping screws in each pair being spaced axially of the ring-formholder.

W1LBERT P; MARSHALI L REFERENCES CITED The following references are ofrecord in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,372,025 Smith Mar. 20, 19452,214,166 Hertlein Sept. 10, 1940 2,107,566 Gardner Feb. 8,19381,047,424 Lumsden Dec. 17, 1912 1,121,995 Elvers Dec. 22, 1914

